Not applicable.
Motorcycle racing has been a popular sport essentially since the evolution of a practical internal combustion engine. Over recent years, this racing sport has migrated to carefully configured dirt courses or tracks wherein typically, about twenty sport motorcycles, which are particularly configured for this sport are raced. The vehicles may be conventionally two-wheeled or three-wheeled. In the former regard, the sport has been coordinated under an organizational movement identified as xe2x80x9cMotocrossxe2x80x9d. Because of these contrived dirt courses, straight stretches will be encountered which are driven at high speeds; curves will be encountered; and jumps will be called for. In the latter regard, a jump is developed from a mound of dirt which, when encountered by the driver and motorcycle, may propel the participant about 15 feet in the air across 85 feet of terrain at speeds typically about 50 miles per hour. As is apparent, the vehicles which are employed for this sport must be quite robust and the power generated by their engines must be maximized to achieve success in this popular racing arena.
Motorcycles used in motocross racing specifically are designed to withstand the rigors of the dirt track while retaining the look of early stock motorcycles. Such a vehicle typically has a bifurcate forward fork assembly with oppositely disposed wheel mounts, each including a resilient compressible tube, these two tubes extend downwardly to attach to opposite sides of a front wheel. The fork assembly extends upwardly to a handlebar. Each of the compressible tubes includes a spring and a shock absorber, creating a front suspension which allows the motorcycles to withstand the substantial forces occasioned, for instance, from jump landings.
Early sporting motorcycles utilized air-cooled motors, however, fluid coolant circulating radiators now are mounted on the frames of the motorcycles. These radiators are located directly behind the forward fork assembly and in front of the cylinder head of the motor. Air cooling is required for radiators. However, the stream of air occasioned by the forward movement of the motorcycles, which otherwise may be directed into the radiators, may be blocked by the front fender. This is particularly true where the front wheel is pivoted to an extent where the rear region of the forward fender will block an adjacent significant proportion of the radiator air confronting surface. With such blockage, the temperature of operation of the motor will tend to increase. Studies in the field have shown that for about each 10xc2x0 F. elevation in temperature of motor operation, as is evidenced at the radiator surface, a loss of about 1 horsepower will be witnessed. In the field of motorcycle racing, a loss of 1 horsepower may have a significant impact on the performance of the motorcycle and its driver. Oil coolers also have been installed in the motor assemblies in view of the importance of temperature control. Generally, these secondary coolers are located behind the main coolant radiators. Of course, the passage of air along the cylinder head region of the motor remains to be important as evidenced by the presence of heat sinking fins which are typically formed with the cylinder heads of the engine.
Another factor that affects the performance of sport racing motorcycles is mud. When the dirt tracks become wet, the resulting mud is flung up from the wheels creating a hazard to the riders. Additionally, this mud adheres to the vehicles adding weight. Of course, weight contributes to a lessening of the dynamic performance of the motorcycle vehicle. Thus, where components of the sports vehicles build up mud layers, performance is diminished to lessen the chances for success in the competitive sporting arena.
Fenders heretofore provided for these two-wheeled vehicles generally are not designed to deal with the particular problems associated with dirt course racing.
The present invention is addressed to fender assemblies and an air transfer and a dirt protection system for motorcycles, particularly sport vehicles intended for racing over dirt courses. Such vehicles achieve racing performance, inter alia, by maximizing the performance of their internal combustion drive motors and by control over the weight build-up due to the adherence of mud particles to their surfaces.
The fender assembly is configured for mounting upon the forward fork assembly of such vehicles in a manner wherein it pivots with and remains in continuous alignment with the plane of rotation of the front wheel. A radiator circulating fluid coolant for the vehicle motor will be located in spaced adjacency with the rear region of the fender assembly. Avoidance of fender caused air blockage to the motor, particularly when the front wheel is turned or pivoted in a steering maneuver, is achieved by the provision of a cooling air transfer duct extending from a forward top surface region air intake scoop on the fender assembly to an air exit opening at a rear region thereof adjacent the air receiving region of the radiator. To enhance the velocity of airflow from the assembly exit opening and, thus enhance the performance of the engine cooling system, the cooling air transfer duct is configured to define a venturi device or tube.
Weight control due to mud buildup is accommodated by the structuring of the fender assembly, in effect, with an upper portion and a lower portion. Because the surface of the upper portion of the fender assembly will carry an ornamentation, it is provided as a molded polyolefin component with a high-shine porcelain layer carrying pigmentation developing an appearance or design desired by the designers. A lower polyolefin molded component combines with the upper portion to evoke the noted venturi device containing air transfer duct. It is the lower or front wheel-confronting surface of this lower portion, which is called upon to block dirt, debris and mud particles, particularly as will be launched by the forward wheel. Accordingly, the undersurface or surface confronting the forward wheel of the lower portion of the fender assembly is configured with a layer of porcelain. However, to conserve weight otherwise developed from pigment materials, this layer is unpigmented.
In a preferred embodiment, the upper and lower portions are provided as discrete components, which are connected together by removable connector assemblies. Thus the assembly can be broken down for cleaning following utilization. Alternately, the upper portion and lower portion may be designed for co-extrusion molding processes to develop a unitary component. It should be recognized, however, that all components can be manufactured also by thermoforming techniques, injection molding techniques, or the like.
With the system of the invention, the front fender assembly with its cooling air transfer duct feature, is configured to perform in conjunction with protective fairings or shrouds which extend downwardly over the vehicle motor at each side of the motorcycle frame. These protective fairings extend from the radiator region along the sides of the cylinder head components of the motor. By configuring them with forward air scoops extending outwardly from the transverse sides of the radiator assembly and by providing an airflow path to an exit opening rearwardly of the fairing-incorporated scoops, the velocity enhanced cooling airflow from the fender assembly can be directed along the cylinder head region of the motor during forward wheel turning maneuvers which would extend a portion of the fender assembly duct exit opening beyond the radiator sides. Thus, an airflow is developed which provides an enhanced thermal exchange with the cylinder head surface region of the motor during intense turning maneuvers.
The protective fairings also may be configured having airfoils located forward of the motor and extending inwardly toward the radiator sides. These airfoils create an additional venturi effect within the system to further increase the flow of air across the heat generating components of the motorcycle. The airfoils open rearwardly to provide airflow communication through the fairings intermediate the forward air scoops and the rearwardly located air exit openings. To facilitate the exhaust of heated air from the system, air exit collectors located rearwardly of the motor may be provided on the side fairings.
Other objects of the invention will, in part, be obvious and will, in part, appear hereinafter.
The invention, accordingly, comprises the apparatus and system possessing the construction, combination of elements and arrangement of parts, which are exemplified in the following detailed disclosure. For a fuller understanding of the nature and objects of the invention, reference should be had to the following detailed description taken in connection with the accompanying drawings.